The field of this invention relates to the stabilization of dried bacterial cells, especially Lactobacilli. The kind of stabilization involved is of such a nature as to permit non-refrigerated, room temperature storage of the bacterial cells while maintaining a high percentage of viability over storage periods of weeks or months. In preferred embodiments, the invention relates to stabilized probiotic Lactobacilli for administration to domestic animals such as chickens, turkeys, swine, cattle, sheep, etc., and/or to small animal pets such as dogs, cats, etc. In fact, the stabilized bacterial suspensions of the present invention are believed useful for administration to a wide variety of birds and mammals.
While many Lactobacilli are potentially useful for probiotic administration, the most widely used lactobacillus for this purpose is L. acidophilus. Dried stabilized concentrates of L. acidophilus have been administered to mammals in milk and other aqueous suspensions. Unless the suspension is to be stored and distributed under refrigerated conditions, such as with commercial acidophilus milk, it has heretofore been necessary to prepare the suspension immediately prior to use in order to be certain that a sufficiently high percentage of the cells administered remain viable at the time of administration.
Lactobacillus cell concentrates can be prepared as described in Porubcan and Sellars U.S. Pat. No. 4,115,199, and these cell concentrates can be dried to obtain stabilized dry cultures as described in Porubcan and Sellars U.S. Pat. No. 3,897,307. Such dried cell concentrates maintain a high percentage of viable cells with room temperature storage and handling. However, the cells are not adequately stable in aqueous suspension unless the suspension is refrigerated. Therefore, in using such stabilized dry cultures in the form of a liquid drench for administration to domestic animals, the cells have been packaged and distributed as a two-part formulation, the dry cell concentrate being packaged separately from the dry suspending agents, both of which must be reconstituted in water prior to use.
There has been a need for a more convenient drenchtype product in which the Lactobacillus cells are prepared in a liquid suspension which can be stored and distributed without serious loss of the viability of the cells. The present invention for the first time, as far as is known, provides a means for preparing products meeting this need.